Handle for a nestable container

ABSTRACT

A handle (200) includes a strap (202), a first boss component (204), and a second boss component (206). The strap has a first end (208) and an opposing second end (209). The first boss component is positioned at the first end of the strap and has a first ledge (218) that extends in a first ledge direction. The second boss component is positioned at the second end of the strap and has a second ledge that extends in a second ledge direction. The first boss component and the second boss component are configured to couple to a first can such that when the first can is nested within a second can the first ledge and the second ledge lie on top of an upper contact surface (106′) of the second can such that the first ledge direction and the second ledge direction are substantially parallel to the upper contact surface.

TECHNICAL FIELD

The present disclosure relates to containers, and more particularly, to a handle used to facilitate nesting and de-nesting of cans.

BACKGROUND

Pails used for industrial and household products such as paint are typically nestable one within another when they are empty. Nesting the pails facilitates stacking, storage, and transport.

One configuration for nestable pails includes a stacking bead that projects outwards from a sidewall of the pail. When the pail is nested into another pail positioned below, the stacking bead contacts an upper surface of the lower pail, which controls how far each pail nests into a corresponding pail. The stacking bead helps minimize space requirements of nested pails and helps reduce the likelihood of pails being stuck together. However, forming the stacking bead requires an extra forming operation which cannot be formed during an expansion process. Also, the contact between the bead and the upper surface of the lower pail can cause scuffing on the bead which can lead to corrosion, and the outer appearance of the pail can be spoiled, such as the brand logo on the front of the pail, because the bead is typically positioned in a center of the sidewall of the pail.

Another configuration for nestable pails includes stacking a pail into another pail positioned below such that a handle ear on the outer surface of the sidewall of the upper pail contacts an upper surface of the lower pail. Typically, the handle ears are cylindrical so the axial load from the nested pails damages the upper surface of the lower pail, such as the lacquer, and can cause two or more dents to be formed on the upper surface. This can lead to corrosion due to the breakdown of the coating and can cause a loss of seal due to the profile of the dented upper surface not matching a corresponding lid.

SUMMARY

A handle for coupling to a pail to improve nesting and de-nesting of one pail into another pail is described. The handle includes boss components on both ends that are configured to couple to corresponding handle ears of a pail. Each boss component includes at least one substantially flat ledge that is configured to lie on top of a curl of the pail receiving the nested pail. To de-nest the nested pail, the handle is configured to rotate about the handle ears causing the nested pail to lift out of the receiving pail due to a force applied by the boss components onto the top of the curl of the receiving pail (e.g. positive de-nesting). Positive de-nesting is useful because pails are often wedged together either due to an excessive axial load during transit, or dents in the body wall. The handle provides a leverage mechanism; the distance from the lifting point on the handle to the axis is approximately 140 mm, and the distance from a cam point of the boss to the axis is approximately 10 mm, which produces a leverage ratio of approximately 14:1, making it much easier to de-stack the pails. Another benefit of positive de-nesting is that a nesting/stacking bead is not required on the sidewall of the pail.

Disclosed herein is a handle for coupling to a pail. The handle includes a strap, a first boss component, and a second boss component. The strap has a first end and an opposing second end. The first boss component is positioned at the first end of the strap, and has a first ledge that extends in a first ledge direction. The second boss component is positioned at the second end of the strap, and has a second ledge that extends in a second ledge direction. The first boss component and the second boss component are configured to couple to a first can such that when the first can is nested within a second can the first ledge and the second ledge are configured to lie on top of an upper contact surface of the second can such that the first ledge direction and the second ledge direction are substantially parallel to the upper contact surface.

Another aspect of the present disclosure provides a method for nesting a first can into a second can. The method comprises: positioning the first can within the second can, the first can including a handle that has a first boss component and a second boss component, the first boss component having a first ledge that extends in a first ledge direction, the second boss component having a second ledge that extends in a second ledge direction; and aligning the first ledge and the second ledge with an upper contact surface of the second can such that the first ledge direction and the second ledge direction are substantially parallel to the upper contact surface.

Another aspect of the present disclosure provides a method for de-nesting a first can from a second can. The method comprises: rotating a handle coupled to the first can from a first position to a second position. The first can includes a handle that has a first boss component and a second boss component. The first boss component has a first ledge that extends in a first ledge direction, and the second boss component has a second ledge that extends in a second ledge direction. In the first position of the handle, the first ledge and the second ledge lie on top of an upper contact surface of the second can such that the first ledge direction and the second ledge direction are substantially parallel to the upper contact surface, and the first can is positioned within the second can by a first depth. In the second position of the handle, the first ledge and the second ledge contact the upper contact surface of the second can such that the first ledge direction and the second ledge direction are angularly offset from the upper contact surface, and the first can is positioned within the second can by a second depth. The first depth is greater than the second depth.

This Summary is provided to introduce a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not constrained to limitations that solve any or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates a front view of a pail, according to an aspect of this disclosure.

FIG. 2 illustrates a perspective view of the pail shown in FIG. 1 with a handled coupled thereto, according to an aspect of this disclosure.

FIGS. 3 and 4 illustrate a front view and a back view of a handle, respectively, in an unbent configuration and not engaged with a pail, according to aspects of this disclosure.

FIGS. 5 and 6 illustrate a back perspective view and a front perspective view, respectively, of a boss component of the handle shown in FIGS. 3 and 4.

FIG. 7 illustrates a back view of a boss component of the handle shown in FIGS. 3 and 4.

FIG. 8 illustrates an alternate aspect of a boss component, according to an aspect of this disclosure.

FIGS. 9-11 illustrate several pails nested within one another, according to an aspect of this disclosure.

FIG. 12 illustrates a perspective view of several pails nested within one another, according to aspect of this disclosure.

FIG. 13 illustrates a side view of several pails nested within one another, with a handle in an engaged configuration, according to an aspect of this disclosure.

DETAILED DESCRIPTION

FIG. 1 illustrates a front view of a pail 100, according to an aspect of this disclosure. The pail 100 may include a can, a bucket, or other container used for industrial and household products. The pail 100 includes a sidewall 102, a base 104, a curl 106, a first handle ear 108, and a second handle ear 110. The sidewall 102 has a substantially cylindrical shape and extends from the base 104 to the curl 106. The base 104 may be seamed to a bottom of the sidewall 102, and the curl 106 may be formed on a top of the sidewall 102 via, for example, a curling process. Each of the first and second handle ears 108 and 110 are coupled to an exterior of the sidewall 102 by using, for example, bolts, welding, adhesives, or other coupling means known in the art. In an aspect, the first handle ear 108 is positioned on an opposing side of the pail 100 with respect to the second handle ear 110, such that each handle ear 108 and 110 is spaced 180° from one another about the exterior of the pail 100.

Certain terminology is used in the description for convenience only and is not limiting. The words “axial,” “longitudinal,” “left,” “right,” “upward,” “downward,” “back,” “front,” “top,” and “bottom” designate directions in the drawings to which reference is made. The term “substantially” is intended to mean considerable in extent or largely but not necessarily wholly that which is specified. The terminology includes the above-listed words, derivatives thereof and words of similar import.

FIG. 2 illustrates a perspective view of the pail 100, according to an aspect of this disclosure. The pail 100 includes a lid 112 and a handle 200 coupled thereto. The lid 112 is configured to couple to the curl 106 positioned at the top of the pail 100. The pail 100 may include a can, a bucket, or other container used for industrial and household products.

The handle 200 is configured to couple to the first and the second handle ears 108 and 110 of the pail 100, as described in more detail below. The sidewall 102, the base 104, the curl 106, and the lid 112 may comprise metal. The handle 200 may comprise a plastic, such as a polypropylene copolymer, a high density polyethylene, or other suitable rugged, typically hard and flexible plastic. Alternatively, the handle 200 may comprise metal to improve sustainability.

FIGS. 3 and 4 illustrate a front view and a back view of the handle 200, respectively, according to aspects of this disclosure. The handle 200 includes a strap 202, a first boss component 204, and a second boss component 206. When the strap 202 is positioned to lie substantially flat, as illustrated in FIGS. 3 and 4, the strap 202 extends along an axial direction A from a first end 208 to a second end 210. The handle 200 may be elongate along the axial direction A, such that a length of the strap 202 is substantially longer than a width of the strap 202. The first boss component 204 is positioned at the first end 208 of the strap 202, and the second boss component 206 is positioned at the second end 210 of the strap 202. In an aspect, a width of the strap 202 towards a center of the strap 202 is less than a width of the strap towards the first and second ends 208 and 210, such that the strap 202 tapers from the first end 208 towards the center of the strap 202 and the strap 202 tapers from the second end 210 towards the center of the strap 202. In an alternative aspect, the width of the strap 202 along its length in the axial direction A from the first end 208 to the second end 210 is substantially uniform. The first end 208 of the strap 202 may be configured substantially similarly to the second end of the strap 210 such that the first end 208 is substantially symmetric to the second end 210 about the center of the strap 202. The first and second boss components 204 and 206 may be coupled to the strap 202, or the first and second boss components 204 and 206 may be integrally formed together with the strap 202 defining a unitary component.

FIGS. 5 and 6 illustrate a back perspective view and a front perspective view of the first boss component 204, respectively, and FIG. 7 illustrates a back view of the first boss component 204. The description provided below is with respect to the first boss component 204, however, it will be appreciated that the description may also apply to the second boss component 206. It will be further appreciated that the first boss component 204 may be substantially symmetric to the second boss component 206 about the center of the strap 202.

The first boss component 204 includes an inner surface 212 and an outer surface 214. The inner surface 212 defines a cavity 216 that opens to the outer surface 214. The cavity 216 has a substantially cylindrical shape and extends in a cavity direction C. The cavity 216 is adapted to receive the first handle ear 108 of the pail 100 therein. In an aspect, the cavity direction C is substantially perpendicular to the axial direction A. The outer surface 214 defines a first ledge 218 and an additional ledge 220. Preferably, the first ledge 218 and the additional ledge 220 are substantially planer and extend along an outer perimeter of the first boss component 204 and form an oblique angle therebetween. It will be appreciated that the first boss component may include fewer or more ledges positioned on its outer perimeter.

With reference to FIG. 7, the first ledge 218 extends along a ledge direction L and the additional ledge 220 extends along an offset direction L′. Both the ledge direction L and the offset direction L′ may be angularly offset from the axial direction A. Both the ledge direction L and the offset direction L′ may be substantially perpendicular to the cavity direction C. In an aspect, the first ledge 218 and the additional ledge 220 are substantially symmetric about the axial direction A. In an alternative aspect, the first ledge 218 and the additional ledge 220 are asymmetric such that the additional ledge 220 may have a length that is shorter than a length of the first ledge 218, which would save a quantity of material used to manufacture the handle 200.

The first ledge 218 extends linearly along the ledge direction L from a trailing end 222 to a leading end 224. The first ledge 218 includes a first trailing portion 226 and a first leading portion 228. The first leading portion 228 extends from the leading end 224 of the first ledge 218 to a point P located between the leading end 224 and the trailing end 222 on the first ledge 218. The first trailing portion 226 extends from the point P to the trailing end 222. The point P is at a location on the first ledge 218 that is closest to a center Ce of the cavity 216. In an aspect, the point P is spaced from the center of the strap 202 by a distance that is shorter than a distance from the center Ce of the cavity 216 to the center of the strap 202. In an aspect, the first leading portion 228 is located closer to the strap 202 than the first trailing portion 226.

The first ledge 218 has a length that extends from the trailing end 222 to the leading end 224 of between approximately 10 mm and 50 mm. In an aspect, the length of the first ledge 218 is approximately 25 mm. A length of the first trailing portion 226 may be less than approximately 15 mm. In an aspect, the length of the first trailing portion 226 may be less than approximately 10 mm. The first leading portion 228 may have a length that is different from the length of the first trailing portion 226. In an aspect, the length of the first leading portion 226 is greater than the length of the first trailing portion 226. It will be appreciated that the additional ledge 220 may be configured substantially similarly as the first ledge 218.

The outer surface 214 of the first boss component 204 further includes a rear ledge 230, a first de-nesting ledge 232, and an additional de-nesting ledge 234. The rear ledge 230 is positioned on a top of the first boss component 204 and extends between the first de-nesting ledge 232 and the additional de-nesting ledge 234. The rear ledge 230 may have a non-linear or curvilinear shape. The first de-nesting ledge 232 is positioned adjacent to the first trailing portion 226 of the first ledge 218, and the additional de-nesting ledge 234 is positioned adjacent to a trailing portion (not labeled) of the additional ledge 220. Both of the first de-nesting ledge 232 and the additional de-nesting ledge 234 may have a non-linear or curvilinear shape. It will be appreciated that the additional de-nesting ledge 234 may be configured substantially similarly as the first de-nesting ledge 232.

FIG. 8 illustrates another aspect of a boss component 304. The boss component 304 may be configured substantially similarly to the first boss component 204, with the exception that the boss component 304 includes a first ledge 318 that has a first trailing portion 326 that has a length that is greater than a length of a first leading portion 328. The lengths of the portions of the first ledges 218 and 318 may be selected based on a desired performance of the handle 200 as further described herein.

The method of using the handle 200 commences by coupling the handle 200 to the pail 100. The first boss component 218 is coupled to the first handle ear 108, such that the first handle ear 108 is positioned within the cavity 216. The second boss component 220 is coupled to the second handle ear 110, such that the second handle ear 110 is positioned within a cavity of the second boss component 220. The first boss component 218 and the second boss component 220 are secured to the first and second handle ears 108 and 110 such that the handle 200 is rotatable about an axis that extends between the first and second handle ears 108 and 110. The first boss component 218 and the second boss component 220 may be secured to the first and second handle ears 108 and 110 by, for example, deforming the first and second boss components 218 and 220 to fit onto (e.g. snap over) the first and second handle ears 108 and 110 to secure the parts together. Alternatively, the first boss component 218 and the second boss component 220 may be secured to the first and second handle ears 108 and 110 by, for example, an integral clip, a rivet component, a bolt or other pinned type connection that allows for rotation between the boss components 218 and 220 and the handle ears 108 and 110.

After the handle 200 is coupled to the pail 100, the pail 100 may be nested into a second pail 100′. FIGS. 9-11 illustrate a first side view, a second side view, and a front view of several pails 100 nested one inside the other. Each pail 100 may have a substantially cylindrical shape that tapers slightly to allow the pail 100 to nest with like pails 100. Each of the pails 100 may be configured substantially similarly as each of the other pails 100.

The pail 100 is nested inside of the second pail 100′ such that the first ledge 218 of the first boss component 204 and a second ledge 219 of the second boss component 206 lie on top of an upper contact surface 106′ of the second pail 100′. When the pails 100 are stacked, the load may cause the handle 200 to rotate such that the ledge direction L of the first ledge 218 and the ledge direction (not labeled) of the second ledge 219 are substantially parallel to the upper contact surface 106′. Stated another way, both the first ledge 218 and the second ledge 219 sit flush against the rim of the second pail 100′. The second ledge 219 may be configured substantially similarly as the first ledge 218. The upper contact surface 106′ may define, for example, a curl. The linear shape of the first and second ledges 218 and 219 prevent damage to the upper contact surface 106′ by spreading the weight of the pail 100 more evenly across the upper contact surface 106′. The linear shape substantially prevents an excessive load to a small area of the upper contact surface 106′ from causing damage to the upper contact surface 106′.

The length of the first and second ledges 218 and 219 may be selected, for example, based on the weight and/or number of pails 100 being nested. For example, if several pails 100 are nested one on top of the other, a longer length of the first and second ledges 218 and 219 may be selected to spread the weight across a larger area of the upper contact surface 106′. Conversely, if a small number of pails 100 are nested on top of one another, a shorter length of the first and second ledges 218 and 219 may be selected, according to the acceptable stress values of the pails, overall weight, and like mechanical parameters.

In an alternative aspect, the first boss component 204 and the second boss component 206 include only a single first ledge 218 and a second ledge 219, respectively. In this aspect, the handle 200 must be oriented prior to coupling to the pail 100 to ensure that the first ledge 218 and the second ledge 219 face the upper contact surface 106′ of the lower pail 100′. A benefit of this configuration (e.g. asymmetric shape) is to save material and produce a smaller and more aesthetic product.

FIG. 12 illustrates a perspective view of the pails 100 shown in FIGS. 9-11 nested within one another. The direction L of the first ledge 218 and the direction of the second ledge 219 may be selected based on a desired length of the handle 200 from the first end 208 to the second end 210. For example, a desired length of the handle 200 is a length such that the handle 200 extends below and contacts a sidewall of a third pail 100″ positioned below the second pail 100′. This desired length may help prevent each pail 100 from prematurely de-nesting. In this example, the direction L of the first ledge 218 and the direction of the second ledge 219 may be selected so that the first and second ledges 218 and 219 lie substantially flat across the upper contact surface 106′ when the handle 200 contacts the third pail 100″.

After the pail 100 is nested inside the second pail 100′, the second pail 100′ may be nested inside a subsequent pail in a substantially similar manner as pail 100 is nested into the second pail 100′. As illustrated in FIGS. 9-11, six pails 100 are nested one inside of the other. It will be appreciated that fewer or more pails 100 may be nested together.

Each pail 100 may be removed from the nested pails one at a time by rotating the handle 200 coupled to each respective pail 100. FIG. 13 illustrates a side view of the nested pails, with the pail 100 being de-nested from the second pail 100′. To de-nest pail 100, the handle 200 is rotated upwards about the axis that extends between the first handle ear 108 and the second handle ear 110 of the pail 100 from a first position to a second position. The first position of the handle 200 is defined by the first and second ledges 218 and 219 lying substantially flat against (that is, in contact with) the upper contact surface 106′ of the second pail 100′. In the first position of the handle 200, the pail 100 is positioned within the second pail 100′ by a first depth that corresponds to spacing controlled by the handle. The second position of the handle 200 is defined by the first and second ledges 218 and 219 being angularly offset from the upper contact surface 106′ of the second pail 100′, upon the handle being rotated upwardly. In the second position of the handle 200, the pail 100 is positioned within the second pail 100′ by a second depth, as the eccentric movement of the boss about the ear centerline drives the upper pail away from the lower pail. In an aspect, in the second position, a distance between the center Ce of the cavity 116 and contact between the first boss component 204 and the upper contact surface 106′ is at a maximum. In an alternative aspect, in the second position, the axial direction A of the handle 200 is substantially parallel to the curl 106 of the pail 100 (see FIG. 13).

The rotation of the handle 200 from the first position to the second position applies a force from both the first boss component 204 and the second boss component 206 to the upper contact surface 106′ of the second pail 100′ that lifts the pail 100 in a direction out of the second pail 100′ from the first depth to the second depth. The first depth is greater than the second depth such that the pail 100 is at least partially removed from the second pail 100′ upon rotation of the handle 200. In an aspect, rotation of the handle 200 from the first position to the second position about the axis that extends between the first handle ear 108 and the second handle ear 110 is less than 90°.

The transition from the first position of the handle 200 to the second position of the handle 200 (e.g. de-nesting stroke) may be adjusted by varying the length of the first trailing portion 226 of the first ledge 218 of the first boss component 204 and/or by varying a length of a second trailing portion (not labeled) of the second ledge 219 of the second boss component 206. A de-nesting stroke distance (e.g. a difference between the first depth and the second depth) is approximately between 2 mm and 10 mm. In an aspect, the de-nesting stroke distance is approximately 6 mm.

As the handle 200 transitions from the first position to the second position, the contact of the first ledge 218 with the upper contact surface 106′ transitions to a contact of the first de-nesting ledge 232 with the upper contact surface 106′. Similarly, the contact of the second ledge 219 of the second boss component 206 with the upper contact surface 106′ transitions to a contact of a second de-nesting ledge (not labeled) of the second boss component 206 with the upper contact surface 106′.

After the handle 200 is rotated to the second position, the pail 100 is de-nested from the second pail 100′, and the pail 100 may be removed from the second pail 100′.

These specific embodiments described above are for illustrative purposes and are not intended to limit the scope of the disclosure as otherwise described and claimed herein. The particular dimensions and materials explained herein are not intended to limit the scope. Rather, a person familiar with nested containers will understand that modification and variations from the described embodiments exist. 

1. A handle comprising: a strap having a first end and an opposing second end; a first boss component being positioned at the first end of the strap, the first boss component having a first ledge that extends in a first ledge direction; and a second boss component being positioned at the second end of the strap, the second boss component having a second ledge that extends in a second ledge direction, wherein the first boss component and the second boss component are configured to couple to a first can such that when the first can is nested within a second can the first ledge and the second ledge are configured to lie on top of an upper contact surface of the second can such that the first ledge direction and the second ledge direction are substantially parallel to the upper contact surface.
 2. The handle of claim 1, wherein when the first boss component and the second boss component are coupled to the first can the handle is configured to rotate between a first position and a second position, wherein in the first position the first ledge and the second ledge lie on top of the upper contact surface of the second can such that the first ledge direction and the second ledge direction are substantially parallel to the upper contact surface, the first can being positioned within the second can by a first depth, wherein in the second position the first ledge and the second ledge contact the upper contact surface of the second can such that the first ledge direction and the second ledge direction are angularly offset from the upper contact surface, the first can being positioned within the second can by a second depth, and wherein the first depth is greater than the second depth.
 3. The handle of claim 2, wherein the handle is configured such that rotation of the handle from the first position to the second position applies a force from the first boss component and the second boss component onto the upper contact surface that lifts the first can in a direction out of the second can from the first depth to the second depth.
 4. The handle of claim 3, wherein a difference between the first depth and the second depth is between approximately 2 mm and 10 mm.
 5. The handle of claim 1, wherein the first boss component defines a first cavity that extends in a first cavity direction, the first ledge direction being substantially perpendicular to the first cavity direction, and wherein the second boss component defines a second cavity that extends in a second cavity direction, the second ledge direction being substantially perpendicular to the second cavity direction.
 6. (canceled)
 7. The handle of claim 5, wherein the first ledge of the first boss component has a first leading portion and a first trailing portion, the first leading portion extending from one end of the first ledge to a point P on the first ledge, the point P being at a location on the first ledge that is closest to a center of the first cavity, the first trailing portion extending from the point P to an opposing end of the first ledge, the first leading portion having a length that is different from a length of the first trailing portion.
 8. The handle of claim 7, wherein the first leading portion is located closer to the strap than the first trailing portion.
 9. The handle of claim 8, wherein the first boss component further includes a first de-nesting ledge, the first de-nesting ledge being non-linear and located adjacent to the first trailing portion.
 10. The handle of claim 7, wherein the length of the first leading edge is greater than the length of the first trailing edge.
 11. (canceled)
 12. The handle of claim 7, wherein the length of the first trailing portion is less than about 15 mm.
 13. (canceled)
 14. The handle of claim 1, wherein the strap comprises plastic.
 15. The handle of claim 1, wherein when the strap is positioned to lie substantially flat such that the strap extends along an axial direction from the first end to the second end the first ledge direction and the second ledge direction are angularly offset from the axial direction.
 16. The handle of claim 15, wherein the first boss component has an additional ledge in addition to the first ledge, the additional ledge extending in a direction that is angularly offset from the first ledge.
 17. The handle of claim 16, wherein the first ledge and the additional ledge are substantially symmetric about the axial direction.
 18. The handle of claim 1, wherein the strap, the first boss component, and the second boss component are integrally formed together defining a unitary component.
 19. The handle of claim 1, wherein when the handle is coupled to the first can the handle produces a positive leverage mechanism having a leverage ratio of approximately 14:1.
 20. A method of nesting a first can into a second can, the method comprising: positioning the first can within the second can, the first can including a handle that has a first boss component and a second boss component, the first boss component having a first ledge that extends in a first ledge direction, the second boss component having a second ledge that extends in a second ledge direction; and aligning the first ledge and the second ledge with an upper contact surface of the second can such that the first ledge direction and the second ledge direction are substantially parallel to the upper contact surface.
 21. The method of claim 20, further comprising: coupling the first boss component to a first handle ear; and coupling the second boss component to a second handle ear, wherein the first and second handle ears are located on opposing sides of a sidewall of the first can.
 22. The method of claim 20, further comprising: rotating the handle coupled to the first can from a first position to a second position, wherein in the first position the first ledge and the second ledge lie on top of an upper contact surface of the second can such that the first ledge direction and the second ledge direction are substantially parallel to the upper contact surface, the first can being positioned within the second can by a first depth, wherein in the second position the first boss component and the second boss component contact the upper contact surface of the second can such that the first ledge direction and the second ledge direction are angularly offset from the upper contact surface, the first can being positioned within the second can by a second depth, and wherein the first depth is greater than the second depth.
 23. The method of claim 22, wherein a difference between the first depth and the second depth is between approximately 2 mm and 10 mm.
 24. (canceled) 